BLue Screen of Death

[Heligrin]

Hi, i played a direct IP multiplayer map with my brother, but then we decided to restart. Now every time i try to load it gives me a Blue Screen of Death from Windows then it forces a hard reboot. It says its an NV display problem, if i read quick enough before it reboots. I cannot play a game with him because i keep getting this error. I can play single player flawlessly!

AMD 3700+
6800GT
Windows SP2
1gb Corsair ram